Currently, active matrix organic light emitting device (“AMOLED”) displays are being introduced. The advantages of such displays include lower power consumption, manufacturing flexibility and faster refresh rate over conventional liquid crystal displays. In contrast to conventional liquid crystal displays, there is no backlighting in an AMOLED display as each pixel consists of different colored OLEDs emitting light independently. Because no backlight is required, an AMOLED display generally consumes less power than a backlight display.
The OLEDs emit light based on current supplied through a drive transistor. The drive transistor is typically a thin film transistor (TFT), and the current level through the drive transistor is dependent on a voltage applied to the gate terminal of the drive transistor. Some displays include capacitors within each pixel to be charged according to programming information and then apply the stored charge to the drive transistor to control its current level. The power consumed in each pixel at any instant is related to the current through the pixel and the voltage across the pixel.